C#基础-连接Access与SQL Server

1.连接Access数据库

 string strConnection = "Provider=Microsoft.Ace.OleDb.12.0; Data Source=" + Server.MapPath("~\\App_Data\\db1.accdb");
 
 OleDbConnection cnn;
 OleDbCommand cmd;
 OleDbDataReader datar;
 
 string str_sql = "select * from T_product where ID=0;";
 cnn = new OleDbConnection(strConnection);
 cnn.Open();
 cmd = new OleDbCommand(str_sql, cnn);
 datar = cmd.ExecuteReader();
 
 while (datar.Read())
 {
      //do something
 }
 
 cnn.Close();

2.连接SQL Server数据库
首先在Webconfig里添加连接字段

<connectionStrings>
    <add name="ApplicationServices"
         connectionString="Server=(local);Integrated Security=SSPI;database=TestServer;uid=***;pwd=***" providerName="System.Data.SqlClient"/>
  </connectionStrings>

然后

 string setting = "ApplicationServices";
 var connString = System.Web.Configuration.WebConfigurationManager.ConnectionStrings[setting];
 
             SqlConnection conn = new SqlConnection(connString.ConnectionString);
             SqlCommand cmd;
             SqlDataReader datar;
             string str_sql = "select * from T_category;";
             conn.Open();
             cmd = new SqlCommand(str_sql, conn);
             datar = cmd.ExecuteReader();
             while (datar.Read())
 
             {
                   // do something
             }
             conn.Close();